Process of refining oils



Jan. 24, 1928. 1,656,990

A. scHwARz PROCESS OF EEFINING OILS inal Filed June 14, 1924 sATURATED HYDROCARBON SULPHURIC AC!D MIXINGJ TANK TREATING v TANK w AX awuemtoz $5 61 ovne Patented an. 24, 1928.

UNITED STATES PATENT OFFICES.

ALFRED SCHWARZ, OF MONTGLAIR, NEW JERSEY, ASSIGNOR TO PETROLEUM SAND PRODUCTS CORPORATION, A CORPORATION OF DELAWARE.

PROCESS OF REFINING OILS.

Application filed June 14, 1924,'Seria1 Ito. 719,942. Renewed December 3 1927.

In the art of producing gasoline, forexample, it is the common practice at present to treat the finished distillate which is obtained in various manners from crude oils 5 and the like, with acids, for example-concentrated or slightly diluted sulphuric acid. Proper means are used for, agitating the sulphuric acid with the oils and as a result of this treatment, highly unsaturated compounds such as the diolefins and a portion of" the olefins, etc. are removed from the oils under treatment, thus improving their quality as motor fuels, as, well as the color of the residual oil. After the acid is agitated with the oil or gasoline it is allowed to settle, it having then formed mostly the sulphonic acids of the hydrocarbons which have reacted with it and the sulphuric acid, as well as the compounds formed by the v :0 acid being very heavy, they readily separate from the mass bysettling and may 'then be drawn off from the remainder. After treatment with sulphuric acid the oil is then Washedwith water-and caustic soda, or subjected to similar treatments. Socalled doctor solutions, composed for example of litha'rge and caustic soda, may be used in connection therewith, to form a sodium-plumbate solution. These solutions so are usually used for the purpose of de-sulphurizing the gasoline.

I have discovered that when the sulphuric acid is not uniformly distributed, as is the case in the prior art, it will attack not only 36 those compounds which it is desired to remove, for example the diolefins, but it will also remove some of the olefins and aromatic oils which it is not desired to destroy. There exists a selective tendency of the sul- 4 phuric acid which, if the acid were perfectly distributed would cause only the weakest compounds for example-the diolefins, to be attacked, and after those are absorbed the next Weakest compounds would be attacked provided there. was more free sulphuric acid available not already diluted to a point of inactivity; When the acid is not properly distributed, this selective reaction will not take place to as great an extent and as a result of this there will be desirable compounds removed fronrthe oils which should not be removed, and sulphuric acid will be used up unnecessarily. It is therefore the purpose of my invention to cause extensive distribution of the sulphuric acid before it is allowed to act upon any of the hydrocarbons and thereafter to contact the so-distributed acid with the .oils to be treated.

It is, of course, not permissible to dilute the acid with water, because its chemical activity toward the hydrocarbons changes materially, depending upon the degree of dilution. I, therefore, first mix the sulphuric acid with a smallpercentage of 'sat- G5 urated hydrocarbons that are diflicultly attacked or, are practically free from attack by sulphuric acid under ordinary conditions, and I thoroughly mix or distribute the sulphuric acid in these saturated hydrocarbons by agitation or otherwise. I then add the mixture, while yet under agitation to the oil, that is also being agitated, thereby causing a very minute and intimate distribution of the sulphuric acid in the oils to be treated at the time of its contact With the oils. In this manner I secure selective reaction with the weakest hydrocarbons first, and I preferably use just sufficient sulphuric acid to remove the weak unsaturated or undesirable hydrocarbons, so that when the substances are removed which it is desired to remove, no more free sulphuric acid is available to attack the remainder of desirable unsaturated hydrocarlmns which should properly remain with the oils under treatment instead ofbeing destroyed and removed. In this manner I save sulphuric acid and save a percentage of the oil under treatment, thus obtaining a result of considerable commercial value.

In the accompanying drawing there is illustrated an arrangement of apparatus by which the process can be conveniently performed. i In the drawings, reference character 1, :indicates a mixing tankthat is provided with an agitator or propeller 2, that may be driven by a motor 3, or, in any other convenient manner. This tank 1, should preferably be square in cross section, so as to cause eddy-currents, thus aiding in the mixing of the oil and purifying agent, or the emulsifieation' of the acid in the saturated hydrocarbons. A supply tank 4, provided with a valved outlet 5 to the tank 1, is provided for the saturated hydrocarbons, and

a supply tank 6 provided with a valved outlet 7 to the tank 1, is provided for the sulphuric acid. A valve outlet pipe 8 leads from the bottom of tank 1 to a treating tank 9 where the oil to be purificdis mixed and treated with the mixture of oil and acid from the tank 1. The tank 9 may be provided with an agitator similar to that shown in tank 1, or the contents of tank 9 may be agitated in any other convenient manner. The tank 9 is provided with a conical shaped bottom 10, so that the spent acid may be conveniently drawn off at the outlet 11, after settling has been permitted to take place. Instead of treating the oil to be purified and the mixture of oil and saturated hydrocarbons in batches as indicated above, these materials may be treated in any of the well known continuous treaters commonly employed.

If desired the solution of caustic soda and litharge or sodium plumbate may be dis tributed or mixed with the sulphuric acid and saturated hydrocarbons after they are introduced into the oils to bepurified. In practice I have found that from one-half to 1 lbs. of sulphuric acid mixed with a gallon of saturated hydrocarbons is sulficient to treat one barrel of oil and obtain the desired color and other qualities of gasoline. 1 It is, of course, understood that the various types of gasoline will require more or less acid and other treatments and no specific statement can be made as vto the quantities to be used in every case. It is also to be understood, that it is not necessary to extract from the treated gasoline, the saturated hydrocarbon that was initially mixed with the acid, but that it may be retained therein. On the other hand, it may be extracted and used over again. In that event, it. is desirable to use a saturated hydrocarbon of either a very low boiling point or a very high boil ing point in order to make it possible to extract the same again from the gasoline after it has been used for the purpose, by fractional distillation. For example, I may use an oil of the kerosene boiling point range, to mix with the sulphuric acid. Such oil is first treated with strong sulphuric acid to remove all the unsaturated hydrocarbons therefrom and it is then ready for: use in connection with my process, for facilitating the distribution of the acid in the oil to be purified. After the acid treatment of the gasoline has been completed, it is customary in prior practice to re-distill the oil in order to extract the remaining quantities of impurities and for the purpose of clarifying the gasoline. In thls same operation the kerosene range product used in my process,

will remain in the still and by suitable connections with a separate condenser, it can be distilled off after all the gasoline has been distilled from the vessel and it may be used again by either thoroughly mixing it with acid and adding it to a new batch of gasoline, or it may be first treated with a small amount of strong sulphuric acid to purify it itself and thereafter it may be used as hereinbefore described.

What I claim as new and desire to secure by Letters Patent, is-

1. The process of refining hydrocarbon oils containing desirable and undesirable unsaturated hydrocarbons which comprises treating such an oil with a mixture of sulphuric acid and saturated hydrocarbons, the sulphuric acid in the mixture being in such amount that only the undesirable unsaturated hydrocarbons are reacted upon and removed from said oil.

2. The process of refining hydrocarbon oils COI'ltzllDlIlg olelins and diolefins which comprises agitating such an oil with a mixture of sulphuric acid and saturated hydrocarbons, the sulphuric acid in the mixture being in such amount that only the diolefins are reacted upon and removed from said oil.

3. The process of refining gasoline containing desirable and undesirable unsaturated hydrocarbons which comprises agitating the same with a mixture of sulphuric acid and saturated hydrocarbons, the amount of sulphuric acid being sufficient to remove the undesirable unsaturated hydrocarbons but insufficient to react upon the desirable unsaturated hydrocarbons.

4:. The process of refining hydrocarbon oils containing desirable and undesirable unsaturated hydrocarbons which comprises treating such an oil with a mixture of sulphuric acid and a saturated hydrocarbon oil differing in boiling point from said first mentioned oil, the amount of sulphuric acid in the mixture being such that only the undesirable unsaturated hydrocarbons are reacted upon, and recovering the saturated hydrocarbon oil for reuse.

The process of refining gasoline containing oleiins and diolcfins which comprises agitating the same with a mixture of sulphuric acid and saturated hydrocarbon oil of higher boiling point than gasoline, the amount of sulphuric acid in the mixture being such as to remove only the diolefins, distilling the resultant mixture of gasoline and saturated hydrocarbon oil, and separately condensing and collecting the refined gasoline and the saturated hydrocarbon oil.

(3. The process of refining hydrocarbon oils containing desirable and undesirable unsaturated hydrocarbons which comprises agitating such an oil with an emulsion of sulphuric acid and saturated hydrocarbons, the amount of sulphuric acid in the emulsion on r 1,656,990 i I v 3' being such that only the undesirable nnsatuamount of sulphuric acid in the emulsion rated hydrocarbons are reacted upon and I8\ being such that only the diolefins are reacted moved from said oil upon and removed. from said oil. 10

7. The process of refining gasoline con- In testimony whereof I afliX my signa- 5 taining olefins and diolefins which comprises ture. agitating the same with an emulsion of sulphuric acid and saturated hydrocarbons, the P ALFRED SCHWARZ. 

